hobbit-alerts.cfg: behaviour of TIME and DURATION together

It seems the combination of TIME=W:0845:2355 and DURATION>15 in
hobbit-alerts.cfg means the earliest an alert can be sent out is 9 am.  Is
this what you would expect?  I would have expected these two rules to mean
the test should be in an alarm colour for more than 15 minutes and be
between the times of 08:45 and 23:55, weekdays.  Instead it seems to be
relating the DURATION with the time such that the DURATION only applies
_during_ the TIME.

If the current behaviour is intended, than will using EXTIME instead of TIME
be what I want?  Oh!  There is no EXTIME?!  I assumed there was but I see no
documentation for it apart from Henrik's suggestion that he might add it:
http://www.hswn.dk/hobbiton/2006/06/msg00417.html

Kind regards,

SebA